tools/perf/build: Remove the volatile-register-var feature check

Namhyung Kim noticed that the volatile-register-var feature check
is superfluous:

 > The gcc manpage says this warning is enabled by -Wall, and we add -Wall
 > to CFLAGS before doing feature checks.  So all gcc versions that support
 > -Wvolatile-register-var enables it by default without this check and
 > older gcc versions will always fail the feature check.

Remove it - this will further speed up feature checks.

Reported-by: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 2 insertions, 6 deletions

diff --git a/tools/perf/config/feature-checks/Makefile b/tools/perf/config/feature-checks/Makefile
index cf33596c7300..2eb83467cca2 100644
--- a/tools/perf/config/feature-checks/Makefile
+++ b/tools/perf/config/feature-checks/Makefile
@@ -25,8 +25,7 @@ FILES=					\
         test-libunwind                  \
         test-on-exit                    \
         test-stackprotector-all         \
-        test-stackprotector             \
-        test-volatile-register-var
+        test-stackprotector
 
 CC := $(CC) -MD
 
@@ -37,7 +36,7 @@ BUILD = $(CC) $(LDFLAGS) -o $(OUTPUT)$@ $@.c
 ###############################
 
 test-all:
-        $(BUILD) -Werror -fstack-protector -fstack-protector-all -Wvolatile-register-var -O2 -Werror -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lunwind -lunwind-x86_64 -lelf -laudit -I/usr/include/slang -lslang $(shell pkg-config --libs --cflags gtk+-2.0 2>/dev/null) $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl
+        $(BUILD) -Werror -fstack-protector -fstack-protector-all -O2 -Werror -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lunwind -lunwind-x86_64 -lelf -laudit -I/usr/include/slang -lslang $(shell pkg-config --libs --cflags gtk+-2.0 2>/dev/null) $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl
 
 test-hello:
         $(BUILD)
@@ -48,9 +47,6 @@ test-stackprotector-all:
 test-stackprotector:
         $(BUILD) -Werror -fstack-protector
 
-test-volatile-register-var:
-        $(BUILD) -Werror -Wvolatile-register-var
-
 test-fortify-source:
         $(BUILD) -O2 -Werror -D_FORTIFY_SOURCE=2